Recording and reproducing apparatus



Aug. 3, 1948. u. 1.. DI GHlLlN l 2,446,324

RECORDING AND REPBODUCING APPARATUS I Filed May 26, 1943 4 Sheets-Sheetl 1948. u. L. Dl GHlLlNl 2,446,324

RECORDING AND REPRODUCING APPARATUS I Filed May 26, 1943 -4 Sheets-Sheet2 Aug. 3, 1948.

U. L. DI GHILINI RECORDING AND REPRODUCING APPARATUS 4 Sheets-Sheet 5Filed May 26, 1943 w Mwuld J L f r Filed May 26, 1943 4 Sheets-Sheet 4RECORDING AND REPRODUCING APPARATUS Patented Aug. 3, 1948 RECORDING ANDREPRODUGING APPARATUS Ulrich a. or Ghilini, BeverlyHills, Calif.;Alexander s. or Ghilini and Elston .di Ghilini, administrators of saidUlrich L., di Ghilinhdeceased Application May 26, 1943, SerialNo.488,515 1 Claim. (01. jam-is) cutting of a like length of sound groovelineage per second on any or all positions of the recording disc,regardless of the changing diameter of same at the point of recording.Constant groove speed reproduction of sound utilizesthe same soundgroove lineage per second as it took ior'the recording of same.

.Both recording and reproducing of sound as described above isaccomplished in part by a constantly changing speed of the turntable onwhich the disc rotates. This compensates for the changing diameter ofthe disc at the point of recording or reproducing.

The general object of the present invention is to provide a constantgroove speed recording and relatively free of friction, and-capable ofbein operated .by amotor having .alow horsepower. Where the mechanicaldesign is maintained =simpie, free of friction,andoperatedby a lowhorsepower motor, better fidelity ofrecording loan be efiected than isthe case where more complicated reproducing apparatus capable of greatlyincreasing the amount of recording time obtainable on asimilar size discused on standard recording machines of the 78 R. P. M. and 33 R. P. M.type, with a higher fidelity and more freedom from disc surface noisesWithout need .of so-called tone-compensation required in .theamplification systems used in conjunction with orthodoxmachines.

The apparatus of the present invention is especially designed to obtaina fluency or smoothness of operation and freedom from mechanical andmotor noises. By means of the present invention, the recording speed isreduced considerably below the recording speeds heretofore employed inrecording apparatus, with the result that the length of time duringwhich recording may becarried out on a given size disc is markedlyincreased over that of usual practice. By decreasing the recordingspeed, i. e., the speed in sound groove lineage per second passingtherecording stylus or reproduction needle point, the surface noisesfrom the recording disc may be decreased.

I have discovered several important mechanical'construction principleswhich determine the fluency and smoothness of operation of a recording(apparatus, and have incorporated mechanical means in the apparatusconsistent with these principles so as to produce a recording andreproducing apparatus of an improvedtype. The first of these principlesis that the mechanical construction of the apparatus should be .as freeas possible from inherent friction. The recording apparatus must besimple in construction,

apparatus having a higher inherentfriction-tand driven by a heaviermotor is employed. :Where more complicated apparatus having higherjriction and usinga heavy motor isemployed, higher recordingv speeds arenecessaryin, ordersto secure fidelity in recordingwvith.theresultithatincreased surface noises .are obtained from the recording disc.

Of primary consideration .in-the construction of the apparatus is theproblem of torque. ffllhe torque in .a recording apparatus increases-thefriction tobe overcome, decreases .thesmoothness of operation, createsdistortion in the recording, tends to produce overlapping of thesoundtracks in recording, increases surface noise, andincreases the.tendency .ofthe. apparatus inrgproducing to fail to follow properly thesoundtrack. The torquein the mechanical construction of a constantgroove speed recording apparatus arises mainly from faulty. design ofthe driveffon the carriage of the apparatus.

In the apparatus of the present.invention,.,the lead screw is positionedrelative 'tothe'supPOr-t for the tone arm on the carriage so as togreatly reduce the torque onfthecarriageyalsotherlistance between thelead screw and the motor carriagecarrying the tone arm is reduced asmuchas possible.

Other factors in the ap aratus of the present invention which tend toimprove the fluen yand smoothness of operation. are that ,thedrivet'fromthe motor operates only the turntabledirectly, the power for moving thecarriage beingtaken from the turntable rather than directly .from,thecarriage. Furthermore, ,a turntable ,light E in weight is employed.

Another object of the present inventionis to provide asound recording.and reproducing-apparatus which is capable of beingoperated-to recordeitherirom the insideto the outsideof'tlie disc, or vice versaifdesired.

Another object. of the invention :is to provide a sound recording andreproducing apparatus-in which .a single recording headis employed -iorboth the purposes of recording and playing back the recording, whichsingle recording head .is provided with a simple mechanicallyactuatedmeans for properly varying the Weight Qnthe recording head -for thesedifierent-purposes.

In theza'pparatus of the ,present invention provision is made formechanically varying the weight on-the recording head-in order toprovide forthe best possibleconditions .of operation for all types ofrecording'disc. -Means also "are'provided jzby which the recording headmay be locked in position during recording so that it is capable ofmovement relative to the carriage only in a vertical plane and also forreleasing the recording head during play-back operations so as to becapable of a limited horizontal movement relative to the carriage.

The sound recording and reproducing apparatus of the present invention,together with various further objects and advantages of the invention,will be fully understood from the following description of the preferredform of the apparatus. The following description is given in connectionwith the accompanying drawings, in which,

Figure 1 it a top plan view.

Figure 2 is a section on the line 22 of Figure 1.

Figure 3 is a side elevation with certain walls of the housing insection.

Figure 4 is a plan view with the top wall of the housing and with theturntable and recording head removed.

Figure 5 is a fragmentary perspective view showing certain of thecontrol mechanism.

1 Figure 5 a, is an enlargement of the buttress thread of the leadscrew.

Figure 6 is a fragmentary section of the feed mechanism in the releasedposition.

Figure 7 is a similar view in the engaged position.

Figure 8 is a fragmentary section of the control mechanism for theattachments for playing standard records.

Figure 9 is a section through the recording arm on the line 99 of Figure2.

Figure 10 is a section on the line l0l0 of Figure 2.

Figure 11 is a fragmentary section, mainly through the recording arm.

from the axis of the turntable 2 at a distance slightly beyond theradius of the turntable 2 or any disc record to be employed thereon. The

Figure 12 is a side view of the recording arm in the elevated position.v

. Figure 12a. shows the position of the yoke relative'to the tube of therecording arm in the elevated position of Figure 12.

Figure 13 is a similar view in the play-back position.

Figure 13a shows the relative positions of the tube and yoke of therecording arm in the playback position of Figure 13.

Figure 14.- is a fragmentary view of a modified form of engagementbetween the carriage and lead screw.

Figure 15 is a section on the line l5--l5 of Figure 14.

Referring to the drawings, the apparatus comprises a turntable 2, whichmay be of any usual or preferred construction, and preferably is lightin weight to insure reduction in friction of the apparatus. Theturntable 2 may comprise a disc portion 3 for the support of a record 4and a stem. The stem is provided with a flange 5 by means of which it isbolted to the disc portion 3. The stem extends through the disc portion2 and is there threaded to receive a nut 6 for clamping the record 4 inposition. The stem extends downwardly into a housing 1 and is providedwithin the housing with a worm for cooperating with a worm wheel 8 on ashaft 9.

The shaft 9 extends substantially radially from the axis of theturntable and is geared to a lead screw l0, The form and position of thelead screw constitutes an important element of the apparatus of thepresent invention. The lead screw ID has a horizontal axis which isspaced lead screw 10 has two threaded portions H and 12. The threadedportions H and I2 are pitched in opposite directions to provide fordriving of the carriage (hereinafter described) in opposite directionswith respect to the turntable from the same direction of rotation of thelead screw. The spacing of the lead screw [0 with reference to the axisof the turntable serves the further function of permitting a reductionin torque and reduction of friction in the operation of the apparatus byallowing the carriage to be driven from a lead screw locatedsubstantially in the same horizontal plane as the point of support ofthe recording arm, as will be hereinafter more apparent.

The apparatus includes the side plates 13 and M, which mount twosupporting rods or tracks 15 and Is for the carriage H. The carriage llconsists of a rectangular frame pivoted, as indicated at Ha, to the rearsupporting rod or track 15. The rear supporting rod I6 is mounteddirectly over the lead screw I0 and parallel therewith, and the distancebetween the lead screw to and rod It should be made small, if possible,in order to reduce the torque arm connecting the carriage with the leadscrew.

The double clutch includes two pivotal feed members 20 and 2|, each ofwhich is pivoted to shaft I9 and is provided with threaded lead shoes 22and 23 for engagement with the lead screw Hi; the shoe 22 being intendedfor forming a driving engagement with the threads I I of the lead screw,whereas the shoe 23 is intended for forming a driving engagement withthe threads of the lead screw 12. Springs 24 and 25 are provided betweenthe frame and the lead shoes for normally urging such members intodriving connection with the threaded portions of the lead screw.

There is also provided a stop or regulator 2M having an adjustment screw25a engaging the feed members for the purpose of governing the depththat the lead shoe enters the lead screw. I have found that asubstantial reduction in friction in operation of the apparatus isobtained by preventing the lead shoe from setting too tightly into thelead screw.

Referring to Figures 14 and 15 of the drawings, I have shown amodification of the feeding mechanism for the carriage, in which thelead screw Illa is permanently in engagement with a gear 90. The gear isloosely journalled on the rod 92 supported by the carriage IIa. In orderto regulate the feeding of the carriage, I provide a brake 93 connectingthe gear 9U with the rod 92.

A clutch control means is provided, which comprises the shaft 25journalled in the rear frame and carrying a sleeve 21 rigid therewith,from which there extends a rod 28, the ends of which rod contact camfaces 29 and 30 on the lead members 20 and 2|. When the rod 28 is in ahorizontal position, it contacts the lead shoes so as to hold both ofthe lead shoes 22 and 23 in disengaged position. Rotation of the arm 28in one direction allows one of the lead shoes to engage the lead screwin under the influence of its spring, whereas rotation of the rod 28 inthe opposite direction permits the opposite lead shoe to engage the leadscrew I 0. The clutch mechanism thus provides means by which thecarriage may be released from driving position with respect to the leadscrew and provides a means by which the carriage may be connected withthe lead screw l0 so as to be driven radially towards the turntableconnected to the lead screw In so as to be driven radially outwardlyfrom the turntable H).

The carriage is provided with a roller 39 for supporting the free end ofthe carriage on the rod I5, the roller 30 being journalled in the frame.The carriage is also provided with an electric motor 3| having a gearreduction box, which is supported in the carriage frame by four rubberbushings 32. The motor 3| is provided with a driving shaft 3,3 includingthe rubber flex ible connection 34'.

To the shaft 33 is pivoted a friction wheel arm 35, which includes twoside plates 35 and end spacer members 31. Journalled between the sideplates is provided a shaft carrying a pulley 3&3 anda friction wheel 39.Pulley 3B is connected by a belt drive to to a pulley 4| on the shaft33. The friction wheel 39 is supported in position beneath the turntable2, so that when the friction wheel arm is pivoted upwardly the frictionwheel engages the underside of the turntable 2 at a point lying on aline passing through axis of the turntable and lying parallel to thedirection of transmission ofthe carriage I! In normal recording andreproducing operations with the apparatus of the present invention, theturntable 2 is rotated by the friction wheel 39, which in turn is drivenby the motor iii. The rotation of the turntable 2 in turn effectsrotation through the worms 3 shaft 9 to the lead screw H). An engagementbetween the lead screw Ill in one of the lead shoes 22 and 23 connectsthe carriage so that it is moved radially with respect to the turntablein operation. The radial movement of the carriage in turn alters theposition of contact between the friction wheel 39 and turntable 2, sothat in operation the speed of rotation of the turntable undergoesconstant change as the friction wheel moves with respect to the axis ofthe turntable, the normal recording and reproduction thus being carriedout with constant linear recording and reproducing speed.

The friction wheel arm 35 isprovided with a rod 42, which is connectedto a spring 43, tensioned to normally pivot the friction wheel arm 35into position to bring the friction wheel 39 into contact with the.turntable 2. A release control lever is provided including an operatingmember 44, which is attached to a cam 45 rigidly attached to the shaft19 of the clutch control means. The cam 45 is shaped so that when theoperating member 54 is rotated upwardly, as viewed in Figure 5, the camengages the rod 42 on the friction wh'eel arm 35, depressing thefriction wheel from driving contact withthe turntable 2. This actionsimultaneously rotates the shaft l9 of the clutch means to insurerelease of both driving lead shoes 22 and 23 from the lead screw It. Inthis position of operation, the friction wheel is disconnected from theturntable, the carriage is released from the lead screw and moved to anydesired starting position.

The apparatus also includes a recording and re-- producing assembly,including a mounting plate 46 which is provided with two verticalmounting pins, by means of which the same is adapted to be detachablysupported on a block 48 having bores 49 to receive the mounting pins 41.This block 48 is positioned on the carriage so as to lie at a pointsubstantially vertically above the lead screw The vertical alignmentbetw n the point of support of the recording mechanism on the carriagecarry pintles 52, to which is pivotally supported a control arm 52a.There is also provided a universally mounted recording head arm 53carrying at its end the electric recording or reproducing head 54 havingthe usual recording or reproducing stylus 55. The recording head arm 53includes the main tube 56 pivoted to the ends of pins 51 carried by theshort sleeve 58. The short sleeve 58 in turn is pivotally mounted by theends of the pintles 52, thus providing for at least a limited universalmovement of-the recording head arm 53. This universal type of mountinghas been found to constitute an important element in the design ofapparatus for faithful reproduction of recordings made at low recordingspeed.

The control arm 52a is intended for weighting the recording arm 53during recording operations. It is well understood in the art that morepressure is required on the stylus 55 during the recording rigidlyconnected to the carriage, whereas in reproducing operations it isdesirable that the weight on the recordin stylus be reduced and at thesame time the recording arm be loosely mounted on the carriage, so thatits position is capable of being governed by the grooves of the recordbeing reproduced. To permit the same recording assembly to fulfill thesedifferent conditions, the control arm 52a is provided. This control arm52a has the yoke fill straddling the arm 53. The yoke 30 has a curvedportion 5! adapted to closely fit the arm 53 when the weighting of thecontrol arm 52a is allowed to be superimposed upon the recording arm 53.The control arm 52a is rigidly supported (as far as horizontal movementis concerned) from the carriage I1, and, thereby when its wei ht isimposedupon the arm 53, it in turn locks such arm 53 rigidly withrespect to the carriage. The yoke 60 of the control arm is provided withan opening of sufficient size so that in one pivoted position of thecontrol arm the recording arm 53 may assume the position shown in Figure1311, where clearance is provided between the recording arm 53 and theyoke. In this position of operation, neither the weight of the controlarm 52a is imposed upon the recording stylus, nor is the motion of thecontrol arm 55 in any way restrained by the yoke 35; on the contrary,the control arm is free to be controlled by the recorded grooves on arecord in reproducing operations. The bottom of the opening of the yokeis provided with a curved surface 62 for engagement with the arm 53, asshown in Figure 12a, when it is desired to elevate the recording armfrom contact with the record in carriageshifting operations.

For controlling and holding the control arm 52a in its various intendedoperating positions, there is provided, as indicated in Figures 12 and13, a cam 63 having a control handle 64, which cam 53 is mounted on apin 65 carried by an ear 56 on the mounting block 48 of the carriage.Figure 12 of the drawings indicates how the rotation of the cam 33 byengagement with the control arm 52a elevates the control arm, andthereby the recording arm 53 into a disengaging position. Figure 13illustrates how in the second position of the cam 63 the control arm52:: is lowered to permit engagement of the stylus 55 with the record inreproducing operations while holding the weight of the control arm 52aof the arm 53. By furtherclockwise pivoting of the cam 63 to the thirdposition, the weight of the control arm 52a is superimposed uponthe arm53 and the apparatus positioned for recording operations.

In order to adapt the recording assembly to the best conditions ofoperation for records of differenttypes, I provide an adjustablecounterbalancing weight 61 slidable into the end of the tube 53andirictionally held in any adjusted position by the spring 63. I havediscovered that for the best reproduction from different records, theWeight of the reproducing arm requires adjustment. The composition ofthe material used'in different records varies. Moreover, reproductionfrom different recordings on the same type of record'may also render itdesirable to vary the reproduction pressure. By the adjustablecounterbalancing weight 67, I have been able to find it possible toconsiderably improve the reproduction in practice. I have also found innumerous cases, for reasons not fully understood, that the adjustablecounterbalance 6! may be used as a tone control adjustment, the amountof Weight imposed on the stylus during reproducing operationsvarying thepitch of the reproducing operations.

In order to adapt the apparatus for reproduction of standard recordsproduced by constant rotary speed in recording, I provide two supplemental drives for the turntable 2. These two supplemental drives areindicated for the reason that there are two rotary turntable speedscommonly used in recording records. more particularly in Figures 3 and 4of the drawings, to the left of the turntable axis there is mounted astationary support supporting a shaft H. Theshaft H is provided With agear 12 adapted to be engaged by a gear 13 on the shaft 33 of thecarriage ll. Whenit is desired to use the apparatus of the presentinvention for reproducing records made by the constant rotary speedmethod, the carriage I1 is disengaged from the lead screw I9 and shiftedto the left into position to engage gears 72 and 73, The friction wheel39 carried by the carriage is disengaged from the turntable and at thesame time the recording head assembly removed. A supplementalreproducing arm 74a is indicated in Figure l for such operations. Inthese operations the record is driven by one of two friction wheels 14and 75. The friction wheels '14 and 15 are carried respectively by thetwo friction wheel arms 12a and 73a pivoted on shaft ll. wheels 74 and75 are spaced radially from the axis of the turntable a proper distanceto give two selective constant rotary speeds to th turntable uponoperation of the motor 3|. These friction wheel arms carry the frictionwheels 14 andv 75 and are provided with rods 16 and I1, by means ofwhich the friction wheels may be pivoted into and out of engagement withthe turntable by cams l8 and 19, controlled by operating members 80-and8|.

Therecording and reproducing machine thus described possesses manyadvantages over those heretofore employed. The machine of the presentinvention may be constructed to operate satisfactorilyat a much slowerrecording speed than As indicated These two friction any other constantgroove speed disc recording machine hitherto commercially sold. Forexample, with the apparatus of the present invention, recording of voiceand music may be carried out at recording speeds of 2.5 inches persecond; whereas the minimum recording speed heretofore employed wasabout 3.85 inches per second for voice and about 8 inches per second forthe purpose of recording music. The standard 78 R, P. M. recordingmachines employ a recording speed of approximately 47 inches per secondon the outside of the disc and 13 inches per second on the inside of thedisc,

Furthermore, the standard recording apparatus is extremely heavy andimpractical for home use.

With the apparatus of the present invention, I may record both voice andmusic over a period of approximately 3 /2 hours on a 16 inch disc, andthis recording time may be increased if voice alone is to be recorded.The standard 78 R, P. M. recording machine records only for about 3.5minutes on a 12 inch disc, whereas the 33 R. P. M. recording apparatusrecords for approximately 15 minutes using the 16 inch disc.

While the particular form of apparatus herein described is well adaptedto carry out the objects of the present invention, various modificationsand changes may be made coming within the scope of the appended claim.

Iclaim:

In an apparatus for recordingand reproducing sound by the constantgroove method, the combination with a carriage, a stylus arm supportedby said carriage, and a motor-driven friction wheel mounted on saidcarriage for driving said turntable, of a feed screw drivenby saidturntable and having two separate oppositely pitched screw portions, andselective means for connecting said carriage selectively with thedifierent portions of said feed screw including a separate half nutcarrying arm engageable with each of said feed portions, said arms eachbeing. provided with spring means normally urging the same into theengaging position, and cam-actuated controlmeans therefor simultaneouslyengaging both of said arms and operative in positions to maintain eitheror both of such arms in the released position.

ULRICH L. m GHILTNI.

REFERENCES orrnn The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Date Number Name 887,429 Rosenthal May 12, 19081,291,515 Hinckley Jan, 14, 1919 1,941,668 Ellman et a1. Jan. 2, 19342,076,298 *I-Iarris 'Apr'. 6, 1937 2,110,223 Harris Mar. 8, 19382,174,167 Rattray Sept. 26, 1939 2,199,420 Sparling May 7, 19402,235,301 Robinson'- 'Mar, 18, 1941 2,273,391 'Yerkovich Feb. 17, 19422,293,217 Rieber Aug. 18, 1942 2,293,220 Rieber Aug. 18, 1942 FOREIGNPATENTS Number Country Date 262,430 Germany; July 12, 1913 639,797 1Germany Dec. 12, 1936

